1. Field of the Invention
The invention relates to a data driver of a display device, and more particularly to a data driver capable of automatically determining an optimum skew and adjusting the clock phase accordingly.
2. Description of the Related Art
Liquid Crystal Displays (LCDs) have become a widely used display device due to its fast response time, light weight, slim profile, high luminance, low power consumption and highly enlargeable display area . . . etc. As the resolution of LCD panels increase, both the number of data drivers (also referred to as source drivers) and transmission speed between the timing controller and the data driver are required to be increased. In order to correctly access data within a valid period, a skew for a system clock (for example, the pixel clock) may be needed. Usually, this period is called the “data valid window”, and its delay with respect to the system clock is called the “skew”.
Conventionally, the skew is manually adjusted to a fixed value when manufacturing the LCD and will not be changed after leaving the factory. However, since the transmission distances between the timing controller and each data driver are different, the fixed skew may not be suitable for all data drivers, thus limiting operation margin of the LCD. Also, the process, voltage and temperature (PVT) variation of data drivers may also cause the fixed skew value to become inappropriate. Thus, a data driver capable of automatically determining an optimum skew and adjusting the clock phase is highly desired.